Bài thi số 3

19:25 Câu 1:
A man drove a car from A to B at speed 60km/h. After arriving B, he took a rest for 30 minutes then turned back to A at speed 40km/h. Known that he started from A at 7:00 am and he reached A again at 3:15pm on the same day. The distance between A and B is km. Câu 2:
The minimum of the expression is Câu 3:
Given that is a positive integer such that and are perfect squares.
The sum of such integers is Câu 4:
Given two triangles and . Known that , and .
If then Câu 5:
How many real numbers are there such that ?
Answer: There are numbers . Câu 6:
The operation on two numbers produces a number equal to their sum minus 2.The value of is Câu 7:
ABC is a triangle. AM is the bisector of angle CAB. Given that AM = 4cm, AB = 6m and AC = 12cm.Then the measurement of angle BAC is degrees. Câu 8:
In the equation above, where is a constant.The greatest possible value of such that the equation has at least one solution is Câu 9:
and are positive integers such that , where is a prime number.
The number of pairs is Câu 10:
Given that .
Calculate:
=
(Input the answer as a decimal in its simplest form) Nộp bài

1) ABC is a triangle where M is the midpoint of segment BC.

MD and ME are two bisectors of triangles AMB and AMC respectively.

If AM= m; BC = a . Then DE = ???

2)\(\dfrac{1}{\left(x+29\right)^2}+\dfrac{1}{\left(x+30\right)^2}=\dfrac{5}{4}\)

What is the product of all real solutions to the equation above?

3) The sum of all possible natural numbers n such that

\(n^2+n+1589\) is a perfect square is.....

4) Given that x is a positive integer such that x and x+99 are perfect squares

The sum of integer x is ...

5)The operation @ on two numbers produces a number equal to their sum minus 2. The value of

(...((1@2)@3....@2017)

6) Given f(x)=\(\dfrac{x^2}{2x-2x^2-1}\)

=> \(f\left(\dfrac{1}{2016}\right)+f\left(\dfrac{2}{2016}\right)+f\left(\dfrac{3}{2016}\right)+...+f\left(\dfrac{2016}{2016}\right)\)

Các bn giúp mk vs >>> tks nha!!!